This invention concerns vessels having a structure buoyed up by pressurized fluid cushions, so-called surface effect vessels.
This invention concerns more precisely surface effect vessels of a type comprising a buoyed up structure with two side keels, a rear seal apparatus and a forward seal apparatus designed to cooperate with the side keels to delimit a central buoyancy cushion supplied by pressurized air generators.
Attempts have already been made to produce such side keel, surface effect vessels.
U.S. Pat. Nos. 3,977,491, 3,987,865 and 4,090,459 and British Pat. Nos. 1,210,973, 1,242,131 or still again the French application for patent No. 2,422,535 for example illustrate different theoretical approaches to these systems.
However in practice, until now the attempts have not proved fully satisfactory insofar as concerns the pounding comfort of the vessel in all sea conditions, the following of the swell, the limitations to leaks and variations in the leak rates around the circumference of the cushions, the crossing of possible obstacles.
The inventors have, in particular, determined that the aforesaid problems encountered with the systems proposed until now were to a great extent due to the methods of supplying the central cushion and the respectively forward and rear seal apparatus on these vessels.
Generally speaking the means proposed until now to delimit the central buoyancy cushion of side keel, surface effect vessels included, forward, a multilobed skirt generally vertically open towards the central cushion, and to the aft, a horizontal extension enclosure.
Most frequently the enclosure forming the after seal is quite separate from the central cushion and connected to the pressurized air generators by associated pipes. The pressurized air supply to the enclosure is quite separate from the central cushion.
According to other and less common proposals, the forward seal apparatus and the rear seal apparatus-multilobe skirt and horizontal enclosure are supplied by separate and respectively associated pressurized air generators, whereas the central cushion is supplied indirectly via the forward and rear seal devices.